Needleless delivery systems

ABSTRACT

A method of treating a prostate condition, including the steps of providing a needleless injector that includes a body at a proximal end, an injection shaft extending from the body to a distal end of the injection shaft, an injection orifice at the distal end of the injection shaft and positioned for fluid ejection in a lateral direction relative to a longitudinal axis of the injection shaft, a pressure source in communication with the fluid chamber, and an extendable tissue tensioner located at the distal end of the injection shaft proximal to the injection orifice; inserting the injection shaft into a urethra so the injection orifice is located within the prostatic urethra; actuating the tissue tensioner to contact urethral tissue, and injecting fluid from the injection orifice into the prostate.

CROSS-REFERENCE TO RELATED APPLICATION

The present patent application is a divisional application of U.S.patent application Ser. No. 11/186,218, filed Jul. 21, 2005, whichclaims the benefit under 35 U.S.C. §119(e) of U.S. Provisional PatentApplication No. 60/634,974, filed on Dec. 9, 2004, the entiredisclosures of which are incorporated herein by reference in theirentireties.

FIELD OF THE INVENTION

The invention relates to methods and devices for treating tissue of thelower urinary tract (e.g., prostate tissue, kidneys, ureters, urethraltissue, bladder, etc.), as well as devices, methods, and surgical kitsfor use in a treatment regimen.

BACKGROUND

Lower urinary tract health is an increasingly important health issue,e.g., based on an aging population. Treatment of lower urinary tractconditions is an area of much investigation.

Prostate disease, for example, is a significant health risk for males.Diseases of the prostate include prostatitis, benign prostatichyperplasia (BPH, also known as benign prostatic hypertrophy), andprostatic carcinoma.

Prostatitis is an inflammation of the prostate gland. Types includeacute and chronic bacterial forms of prostatitis, and a non-bacterialform. Symptoms can include difficult urination, burning or painfulurination, perineal or lower back pain, joint or muscle pain, tender orswollen prostate, blood in the urine, or painful ejaculation.Prostatitis is caused by bacterial infection in many instances, in whichcase treatment generally includes antimicrobial medication.Noninfectious forms of prostatitis are treated by other means such asadministration of an alpha-1-adrenoreceptor antagonist drug to relax themuscle tissue in the prostate and reduce the difficulty in urination.

Benign prostatic hypertrophy (BPH) is a very common disorder affectingan estimated 12 million men in the United States alone. BPH is a chroniccondition and is strongly age-related; approximately 50% of men over theage of fifty, 75% of men beyond the age of seventy, and 90% of men overthe age of eighty are afflicted with BPH. BPH is a non-cancerouscondition characterized by enlargement of the prostate, obstruction ofthe urethra, and gradual loss of bladder function. Symptoms includedifficult urination, frequent urination, incomplete emptying of thebladder, and urgency.

BPH may be treated with a number of therapeutic modalities includingsurgical and medical methods, depending on severity of symptoms.Treatments range from “watchful waiting” for men with mild symptoms, tomedications, to surgical procedures. Examples of useful medicationsinclude 5-alpha reductase inhibitors such as Avodart™ and Proscar®.

Transurethral resection of the prostate (TURP) is a preferred surgicalmethod of treating BPH. A typical TURP procedure requires generalanesthesia and the placement of a resectoscope in the urethra forremoval of multiple small chips of hyperplastic prostatic tissue torelieve the obstruction. Complications from TURP include bleeding,incontinence, retrograde ejaculation, and impotence.

An alternate surgical method for treating BPH is transurethral incisionof the prostate (TUIP). In the TUIP procedure, incisions are made in theprostate to relieve pressure and improve flow rate. Incisions are madewhere the prostate meets the bladder. No tissue is removed in the TUIPprocedure. Cutting muscle in this area relaxes the opening to thebladder, which decreases resistance to urine flow from the bladder. Avariant of the TUIP procedure in which a laser is used to make theincision is known as transurethral laser incision of the prostate(TULIP).

Other surgical methods used to relieve the symptoms of BPH includemethods of promoting necrosis of tissue that blocks the urethra.Hyperthermic methods, for example, use the application of heat to “cook”tissue and kill the cells. The necrosed tissue is gradually absorbed bythe body. Several methods of applying heat or causing necrosis have beendemonstrated, including direct heat (transurethral needle ablation, orTUNA), microwave (transurethral microwave treatment, or TUMT),ultrasound (high-intensity focused ultrasound, or HIFU), electricalvaporization (transurethral electrical vaporization of the prostate, orTUEVP) and laser ablation (visual laser ablation of the prostate, orVLAP), among others.

Chemical ablation (chemoablation) techniques for promoting prostatetissue necrosis have also been considered. In one chemical ablationtechnique, absolute ethanol is injected transurethrally into theprostate tissue. This technique is known as transurethral ethanolablation of the prostate (TEAP). The injected ethanol causes cells ofthe prostate to burst, killing the cells. The prostate shrinks as thenecrosed cells are absorbed.

SUMMARY

The invention relates to needleless devices useful for injecting fluidto tissue of the lower urinary tract such as the prostate. The devicesinject a therapeutic fluid or “injectate” at high-pressure using anorifice at the end of an elongate shaft inserted into the urethra. Totreat the prostate, the injectate fluid passes through the urethra anddisperses in the prostate as a cloud of particles.

Various treatments of the prostate that are currently used or proposed,such as transurethral chemical ablation or administering an activepharmaceutical, involve injection of a therapeutic fluid into theprostate using a needle located in and passed through the urethra. Theuse of a needle to inject a therapeutic fluid such as a drug or ethanolcan involve various difficulties or undesired effects due to thestructure of the prostate and the manner and nature by which a needledelivers a fluid by injection.

Generally, injection using a needle is inherently susceptible to flow ofa liquid injectate back through the tissue path created by the needle,i.e., “backflow.” Fluid that is pressurized to flow from the tip of theneedle into desired tissue can flow back out of the tissue through thepath of the needle causing that amount of the liquid to be ineffectivein treating the targeted tissue.

Specifically with respect to injecting the prostate, this organ has aglandular structure that contains its own fluid ducts for channelingbiological fluids to the urethra. When injecting fluid to the prostategland using a needle, the utility and performance of a needle is limitedin that a needle can inject a volume of fluid only at a discretelocation (“bolus”) in the prostate. An injected volume of fluid cantypically produce a pool (bolus) of fluid at the injection site at theneedle tip. This pool collects at an isolated location within the highlyducted structure of the prostate. The pool of injected fluid willnaturally flow through the ducted structure of the prostate leading outof the prostate and into the urethra where the fluid is not desired oreffective.

A result of the pooling of an injectate delivered to a prostate using aneedle, and the undesired flow of the injectate through ducts of theprostate, is that a substantially larger volume of injectate must bedelivered for treatment because much of the injectate is carried awayfrom the desired treatment site within the prostate. The total amount offluid delivered must account for the amount that is therapeuticallyeffective and the additional amount that is lost, meaning that a largertotal volume of fluid must be injected, i.e., an overdose.

Another disadvantage of the use of a needle to inject fluid into theprostate is that an injection through a needle must be delivered slowly,to minimize back-pressure and consequent pooling of the injected fluidduring injection into the prostate, and to avoid backflow of theinjectate along the tissue path of the needle.

The invention relates to devices, systems, and methods for using aneedleless system for transurethral injection of a fluid (“injectate”)to tissue of the lower urinary tract, such as the prostate. Theneedleless systems can overcome undesired or disadvantageous features ofsystems and methods that use a needle, e.g., for transurethralinjections of fluid into the prostate.

A needleless injection does not cause an injected fluid to pool at alocality within injected tissue as does injection of a fluid using aneedle. As opposed to a pool of fluid, a fluid that is injected intotissue by a needleless injection system becomes dispersed as droplets orparticles of liquid that enter an injected tissue and disperse withinthe tissue. The injected fluid, in the form of droplets, does not flowinto pools that could allow for backflow through a tissue path or thatcould potentially reach a gland duct to flow, e.g., from the prostateinto the urethra. Preferably, an injectate delivered by needlelessinjection can be in the form of a fine mist that advantageously isdistributed as a cloud of particles or droplets throughout injectedtissue.

An attendant advantageous effect of a needleless injection compared tothe use of a needle is that the total amount of fluid injectate isreduced because there is no loss from flow out of the injected tissue.There is no need for “overdosing” as with the use of a needle.

A needleless mode of injecting a fluid into the prostate or other tissueof the lower urinary tract requires that certain technical challenges beovercome to accommodate the specific technical and medical needs ofinjecting a therapeutic fluid to internal tissue, optionallytransurethrally, without a needle. For instance, to inject the prostate,a needleless injector must be of a size and shape that may be placedwithin the urethra while also providing an injectate at the injectionorifice in the prostatic urethra at a pressure sufficient to penetrateurethral and prostate tissues. The injectate must penetrate urethral andprostate tissues in a predictable and desired fashion to becomedispersed throughout the prostate tissue.

A particular need for delivery of a therapeutic fluid to tissue of thelower urinary tract is that the injected fluid must be delivered atdistance (i.e., “throw”) from a pressurized source of fluid.Specifically, the delivery site is a distance from the source of thetherapeutic fluid, through a length of shaft, and the delivery may be ina direction that includes a directional component directed away from thelongitudinal axis of the shaft, i.e., delivery may be performed awayfrom the tip of a shaft and in a direction that is not the same as theaxis of the shaft.

Additionally, injected fluid is desirably dispersed throughout theinjected tissue. Needleless delivery of a therapeutic fluid to prostatetissue, for example, is best if the therapeutic agent is disperseduniformly throughout the prostate as droplets or particles. An enlargedprostate is not typically enlarged homogeneously but includes isolatedenlarged nodules potentially throughout. The location of the enlargedportions are not typically precisely known, so it is considered goodtreatment practice to disperse therapeutic agent throughout the entireprostate.

Furthermore, the location of the lower urinary tract as internal organs,and delivery optionally through the urethra, result in an importance tobeing able to precisely position a needleless injection orifice forinjecting a fluid. Particularly desirable features of a needlelessinjector may include features that facilitate placement of injectionorifices at desired locations for injection, e.g., an optical devicethat allows for viewing of internal tissue.

Still additionally, inadvertent, misplaced, or incorrect actuation of aneedleless injection system at a time when the system is installed orpartially installed, would normally result in severe injury to urethraltissue, prostate tissue, or any other tissue exposed to anincorrectly-performed injection. For instance if an injection mechanismwere actuated when a needleless injector device does not properlycontain a liquid in the injection lumen, causing air to be ejected,great injury would result to affected tissues. As such, safety featuresthat prevent inadvertent or incorrect actuation of the injectionmechanism are very important.

Features of needleless injector devices described above are included aspart of the present disclosure and may be included in a needlelessinjector device individually or in any desired combination. For example,embodiments of the invention include needleless injector devices thatinclude positioning features that facilitate proper positioning of aninjection orifice in the urethra. Positioning features are various innature and may include one or more of: a balloon or multiple balloonslocated at the distal end of the device for placement and fixing thedistal end; multiple orifices; moveable orifices; demarcation ofdistances to distal end features, at the proximal end; and an opticalfeature such as an endoscope or optical fiber. Other embodiments ofneedleless injector devices include the above features along with one ormore tissue tensioners that contact and optionally place pressure ontissue at a desired location relative to an injection orifice, andoptionally can also place a strain or tension on the tissue as desiredfor delivery of an injection at the surface of the tissue. Examples oftissue tensioners include inflatable or extendable features such asballoons or mechanically extendable features such as paddles, metalcages, other mechanically extendable protrusions, vacuum, etc.

Needleless injector devices as described can be used with variousdelivery methods such as methods that allow for direct vision of aninjection wherein an internal location of an injection orifice isdetermined visually, and methods referred to as blind delivery methodswherein location of an injection orifice is determined indirectly.Direct vision methods involve the use of an optical feature to view aninjection site directly, such as by use of an endoscope or optical fiberthat is included in an injector device, e.g., as a component of theshaft. A device that allows for blind delivery can instead include oneor more non-optical features that allow a surgeon to identify theposition of a device, and in particular an injection orifice, e.g.,within the urethra, so that an injection can be performed at a desiredlocation. Blind delivery techniques can identify a delivery locationbased on features of the device such as a length-measuring feature suchas demarcations at the proximal end of the device that referencelocations of features at the distal end, by using demarcations incombination with known dimensions of a device and of anatomy.Demarcations may be used also in combination with measurement ofanatomical features such as the length of the prostate, e.g., by knowntechniques including those that use ultrasound position measuringequipment. Blind delivery techniques can also involve other features ofdevices as described herein such as positioning features (e.g., balloonsat the distal end of the device) and moveable injection orifices.

Various embodiments of injector devices of the invention can includedifferent types of shafts, including a flexible shaft, a rigid shaft, amulti-piece shaft designed to be assembled and disassembled prior to orfollowing use, and an integral shaft that is not designed to beassembled and disassembled prior to or after use. Particular devices andmethods of the invention involve shafts that are flexible integralshafts wherein the device does not include an optical device such as anendoscope but includes positioning features such as balloons, and isused with blind delivery methods. Other devices and methods involvemulti-component shafts that include an endoscope and other features asdescribed herein.

Various embodiments of the invention can optionally or alternatelyinclude safety features that prevent inadvertent or improper ejection offluid from a device, and features that add convenience or efficiencysuch as trigger mechanisms, systems and methods that allow for multipleinjections, methods of controlling or programming volumes, depths, orother features of one or multiple injections.

An aspect of the invention relates to a needleless injector device. Thedevice includes a body at a proximal end; a shaft extending from thebody to a distal end of the shaft; an injection orifice at the distalend of the shaft in fluid communication with a fluid chamber at theproximal end, the injection orifice directed away from the longitudinalaxis of the shaft; a pressure source in communication with the fluidchamber, and a tissue tensioner located at the distal end of the shaftproximal to the injection orifice.

Another aspect of the invention relates to a needleless injector devicethat includes a body at a proximal end; a flexible shaft extending fromthe body to a distal end of the shaft; an injection orifice at thedistal end of the shaft in fluid communication with a fluid chamber atthe proximal end; and a pressure source in communication with the fluidchamber.

Yet another embodiment of the invention relates to a needleless injectordevice that includes a body having a fluid chamber; a shaft extendingfrom the body to a distal end of the shaft; an injection orifice at thedistal end of the shaft; an injection lumen connecting the injectionorifice and the fluid chamber; and a priming mechanism capable offilling the injection lumen by low pressure flow of fluid from the fluidchamber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary components of a shaft of an injectordevice of the invention.

FIGS. 2 and 2 a illustrate exemplary components of a shaft of aninjector device, including tissue tensioning features and features ofinjector heads.

FIGS. 3 and 3 a illustrate exemplary components of a shaft of aninjector device, including tissue tensioning features and features ofinjector heads.

FIGS. 4 a, 4 b, 4 c, and 4 d illustrate exemplary components of a shaftof an injector device, including tissue tensioning features.

FIGS. 5, 5 a, and 5 b, illustrate exemplary components of an injectordevice.

FIG. 6 illustrates exemplary components of a body of an injector device.

FIG. 7 illustrates a portion of anatomy of the lower urinary tract.

FIGS. 8 and 9 illustrate exemplary injector devices as installed duringuse.

All drawings are schematic and not necessarily to scale.

DETAILED DESCRIPTION

Devices, systems, and methods are provided that allow for needlelessinjection of a therapeutic fluid (“injectate”). The devices may be usedfor various applications related to conditions of a lower urinary tractsuch as the urethra, bladder, kidney, ureters, prostate, etc. In oneparticular method an injectate such as a pharmaceutical or ablativeagent can be injected transurethrally, without a needle, into theprostate. The devices are designed to place an injection orifice at adesired location within the lower urinary tract to allow needlelesstransurethral delivery (i.e., injection) of therapeutic fluid to desiredtissue.

The invention identifies and addresses certain practical problemsassociated with other modes of injecting fluid into tissue of the lowerurinary tract. For example, injection of fluid to the prostate by use ofa needle can cause pooling of fluid in the highly-ducted structure ofthe prostate resulting in undesired flow of the fluid away from theintended therapeutic location in the prostate. Needleless injectordevices and methods as described herein are advantageous compared to theuse of a needle for various reasons including that the needlelessinjection produces an injection in the form of a cloud of dispersedparticles of injectate that penetrates the injected tissue anddisperses. Advantageously, these injected particles do not pool.

The devices and methods include various features discussed herein, anyof which can be used either separately or in combination with any one ormore of the other described features. The features include thefollowing: construction of a shaft of the device in multiple, separablepieces, or as a single “integral” piece; a rigid shaft or a flexibleshaft; features relating to the number and positioning of injectionorifices such as multiple injection orifices located at differentpositions along a length of a shaft of a device or located at differentpositions around a perimeter of a shaft of the device, and moveableinjection orifices that may be moveable along a length of a shaft,around a perimeter of a shaft, or along a length and around a perimeterof the shaft; one or more tissue tensioners to contact tissue near aninjection orifice and manipulate the tissue as desired during injection;locating features such as balloons or other mechanisms to fix thelocation of a portion of a device, e.g., within the urethra; safetyfeatures that prevent inadvertent or improper actuation of a device orejection of fluid from a device; and features that add convenience orefficiency such as specific trigger mechanisms, systems and methods thatallow for multiple injections or dosages, and methods and features forcontrolling or programming volumes, depths, timing, order, positioning,or other features of one or multiple injections.

Generally, an injector device can include a body at a proximal end, thebody including one or more fluid chambers. A shaft is attached to thebody. A fluid chamber can be a fluid reservoir, a syringe chamber, or adevice may include both. A reservoir can refer to a fixed-volume holdingspace for injectate fluid and need not (but may) be capable of beingpressurized to low or moderate pressure or highly pressurized, e.g.,pressurized to allow for priming or to cause injectate fluid to beejected from an injection orifice by way of an injection lumen. Areservoir can be sized to contain one or multiple volumes of injectate,and may be in the form of a removable or replaceable vial.

Another exemplary type of fluid chamber is referred to as a syringechamber, which is a chamber that has a variable volume based, e.g., on aplunger, piston, bellows, or other mechanism for increasing ordecreasing the volume (and pressure) of the chamber. A syringe chambercan be pressurized by a pressure source attached to the plunger,bellows, or piston such that injectate fluid contained in the syringechamber is ejected under pressure from the syringe chamber, either forpriming or for injecting tissue. The injectate flows into an injectionlumen in a shaft of the device, and from an injection orifice at thedistal end of the shaft. The pressure source may be any source of energysuch as a spring, compressed air, manual syringe, electric power,hydraulic, pneumatic pressure sources, etc.

Attached to the body, a needleless injector device of the invention caninclude an elongate shaft for placement within the urethra. The shaftincludes an injection orifice located to inject fluid to internaltissue, e.g., through the urethra and into the prostate, when the deviceis installed.

The device includes a distal end and a proximal end. A distal end,including a shaft, generally is considered to include the portion of thedevice that is located internally within a patient's body during atreatment procedure. A distal end will typically include functionalfeatures that operate on tissue during use, such as an injectionorifice, an injector head if used, one or more balloons or other form ofpositioning devices if used, and tissue tensioners if used.

A proximal end of a device includes a portion that remains external tothe patient during use, (e.g., the body). A proximal end generallyincludes features that are not required to be internal during atreatment procedure such as a source of injectate and a source ofpressure for the injectate; an eye-piece of an endoscope or otheroptical feature if included with the device; mechanical features such asa trigger or handle for holding or actuating a body or another featureat the distal end; adapters for attaching the proximal end toappurtenant equipment such as a source of power, a source of pressure, asource of fluid, or a source of vacuum, etc.

A shaft of an injector device may be an elongate component that ingeneral extends from the proximal end to the distal end and includesfeatures and componentry that allow for use and operation of distal endfeatures by use and operation of proximal end features. A shaft maygenerally be of various constructions, as desired, e.g., may be of anintegral construction that is not designed to be assembled anddis-assembled prior to, during, or after use; or may be of a multi-piececonstruction that includes multiple elongate shaft components orelements that fit together as an assembled whole for use in a surgicalprocedure and that can be assembled and dis-assembled before and afteruse if desired.

Either of a multiple-component or an integral construction-type shaftmay be flexible or rigid and either type may include any of the featuresof devices described herein. Metal or polymeric materials may be usefulfor either type of shaft or for a component of either type of shaft.Materials that can be particularly useful for a rigid, multi-piece shaftmay include rigid polymeric materials such as a rigid plastic or a rigidmetal material. Specific examples include nitinol, polycarbonate,stainless steel, and the like. Materials useful for a flexible shaft ora flexible component of a multi-piece shaft can be relatively flexiblepolymeric materials such as polymeric materials known to be useful forcatheter devices such as urethral catheters (e.g., Foley catheters).Specific examples of flexible polymeric materials include silicones,polyurethanes, rubbers, latex, and the like.

A single-component or “integral” shaft for an injector device is a shaftthat is substantially or completely assembled at the time of manufactureof the device and that is not designed to be assembled or dis-assembledprior to or after use. The shaft may be flexible or rigid and may beprepared from metal or polymeric materials. A flexible integral shaftincludes a flexible elongate component that extends from a proximal to adistal end of the injector device, and that defines or includesnecessary functional elements such as injection orifices, lumens, etc.,to operate the features at the distal end from the proximal end. Thesefeatures of the shaft portion of the device are substantially permanentfeatures of the device that are not designed to be removed from ordis-assembled into multiple components of a shaft.

According to certain embodiments an integral shaft can be a flexibleshaft prepared from a flexible polymer, and can include lumens thatconnect distal end features to the proximal end of a device. The lumenscan be flexible lumens defined by or embedded in the shaft or in a wallof the shaft. If necessary a lumen can be of sufficient strength towithstand elevated pressures such as in the case of an injection lumenthat connects an injection orifice at a distal end to a pressurizedsupply of injectate fluid at a proximal end. Exemplary elevatedpressures (“injection pressures”) may be 2000 pounds per square inch orgreater. An injection lumen may be of a flexible material (e.g., a metalor polymeric tube) that can withstand such an injection pressure, andmay be prepared from exemplary materials capable of withstandingpressure of an injection, e.g., nitinol, stainless steel, reinforced(e.g., braided) polymer.

“Flexible shaft” refers to a shaft that is sufficiently pliable to allowbending and flexing that allow the shaft to be inserted through themeatus and to allow a portion of a distal end of the shaft to be guidedinto the urethra as can be done with a Foley catheter.

An integral shaft can be prepared with materials and methods similar tothose used to prepare known urethral catheter devices such as a Foleycatheter, but adapted to include a needleless injection mechanism andoptionally other features as described herein. An integral shaft mayinclude any one or more of: one or multiple injection orifices; moveableinjection orifices; tissue tensioners; balloons for locating the device;an optical feature such as an endoscope or a flexible fiber optic cable;etc. Any one or more of these features can be located along a desiredlength of a device or at a specific location at a distal end of adevice, along the integral shaft, and can be functionally connected tothe proximal end by lumens or actuating mechanisms.

An integral shaft can be particularly useful with devices that include aflexible shaft and that contain a tissue tensioner or a device-locatingfeature such as one or more balloons at the distal end for locating thedevice during use. The use of a device-locating feature mayadvantageously eliminate the need for an optical feature such as anendoscope, allowing for injections to be carried out with blind visionmethods. Particular devices of the invention may include an integralflexible shaft, injection orifices, one or more tissue tensioners, andother features of a urethral catheter such as one or more inflatableballoons at the distal end, and a drainage orifice at the tip and adrainage lumen leading from the bladder (when installed) to the proximalend of the device. Such devices, including a flexible shaft, a drainagelumen to drain urine from a bladder (e.g., as does a Foley catheter),and optional balloon, may be referred to as an “injection catheter”embodiments of the invention. In use, “injection catheter” embodimentsmay be inserted through the external orifice of the urethra (meatus) aswith a Foley catheter, as opposed to being inserted through an externalincision and a tissue path to the urethra as with rigid-shaft injectordevices.

As opposed to an integral shaft, shafts referred to as“multiple-component” shafts may include two or more elongate pieces orcomponents that fit together as an assembled whole and that can bedis-assembled prior to or after use. Typical components of amultiple-component shaft include an outer shaft or “sheath” in the formof an elongate rigid hollow sheath, and one or more additional innershaft components that can be assembled together with the outer shaft toform a functional, assembled, multi-component shaft.

An outer shaft or “sheath” of a multiple-component shaft may be a basicsheath that is sized and shaped to be placed in the urethra whilecontaining one or more inner shaft components. A sheath component of amulti-piece shaft may include just a hollow and rigid sheath, or mayinclude a hollow and rigid sheath having functional features of a devicesuch as one or more of a tissue tensioner, an injection lumen orinjector head, a positioning component such as one or more balloons, andone or more lumens that connect a functional feature at the distal endof the sheath to the proximal end. An exemplary outer shaft can be arigid (e.g., of metal or a rigid plastic) sleeve that can be inserted ina patient from an external incision, to define a passage from theexternal incision into the prostatic urethra. When inserted, one or moreinner shaft components can be inserted into the outer shaft, as desired.

An inner shaft component of a multi-component shaft can fit within theouter shaft component or sheath and may include one or multiplefunctional features of a device such as one or more injection orifices,one or more lumens, one or more injector heads, or an optical featuresuch as a lens, open viewing channel, tissue tensioner, etc. An innershaft that includes an injector head or an injection orifice may bespecifically referred to as, e.g., an inner “injection shaft,” and mayinclude an injection orifice at a distal end connected through aninjection lumen to a proximal end of the inner (“injection”) shaftcomponent. Optionally, an inner shaft component (or a feature thereofsuch as an injection orifice or an injector head) can be moveable withinan outer shaft component or shaft generally, for any reason, such as toallow movement of an injector head or injection orifice during use.

Also optionally, as desired, embodiments of the invention may combinemultiple device features into a single rigid shaft component. Forexample, a rigid shaft component may combine an outer sheath with aninjection shaft, and may be sized and shaped to receive an endoscope.Alternately a rigid shaft component may combine an outer rigid sheathwith an endoscope, and may be sized and shaped to receive an inner“injection shaft” that contains an injection lumen and injectionorifice. As yet another alternative, the endoscope may also be combinedwith an outer shaft component and injection features into a single rigidshaft that is not designed to be assembled and disassembled.

Generally, any of the various shaft designs may be used with eitherblind vision methods or direct vision methods. An optical feature can beincorporated into any of a multiple-component, integral, rigid, orflexible shaft, using known materials and constructions, such as with anendoscope or any form of fiber optic device or other optical device. Aneyepiece can be located at the proximal end of a device and one or moreof an open vision channel, optical fiber, lens, multiple lenses,mirrors, refractive or reflective devices, or combination of these, canbe used to create visual communication between the proximal end and alocation at the distal end of the device. For a flexible shaft, forexample, a flexible optical fiber can run from an eyepiece at theproximal end of the device to the distal end of the device at a locationalong the shaft. The optical fiber allows viewing of the distal end ofthe shaft, e.g., at a location to view an injection orifice.

With direct vision methods an optical feature such as an endoscope oroptical fiber, etc., can be used to view internal tissue such as theinternal urethra to facilitate placement of an injection orifice ormultiple injection orifices as desired, e.g., within the prostaticurethra. Blind vision methods, on the other hand, can eliminate the needfor an optical feature such as an endoscope and may instead rely onpositioning of an injection orifice or orifices by use of other featuressuch as the known dimensions of a device or positioning features at thedistal end of the device, e.g., one or more of a distal or a proximalballoon, distance demarcations at the proximal end of the device, tissuetensioner, moveable orifice, which together can allow for blinddelivery.

Any combination of shaft properties (e.g., rigid or flexible shaft) andother features described herein can be useful in injector devices, asdesired. Certain specific features or combinations of features may beparticularly useful with either rigid or flexible shaft designs. A rigidmulti-component shaft may be particularly useful in combination with adirect vision feature and may optionally exclude the use of other typesof positioning features such as one or more balloons at the distal endof the device. In addition, a rigid shaft may optionally not require theuse of a tissue tensioner because a rigid shaft can be used to applypressure between an injection orifice or injector head at a distal endof a device, and internal tissue. Still, a tissue tensioner may bedesirable or useful as part of a device that includes a rigid shaft,e.g., those that include an injector head that places a small distancebetween an injection orifice and internal tissue at the site ofinjection (see below).

Certain integral, flexible shaft embodiments of devices may be useful asincluding a flexible shaft and can provide advantages such as patientcomfort due to the flexible shaft, elimination of the need for anexternal incision to access the urethra (as is normally used with rigidshaft designs) and optionally the use of blind vision injection methodsbased on the use of positioning features such as balloons at the distalend of the device. These devices may include a flexible shaft thatincludes features for placing and fixing the distal end of the device tolocate one or more injection orifices as desired, e.g., within theprostatic urethra (i.e., “positioning features”). Advantageously, theflexible shaft may be inserted through the external urethra orifice(meatus) (e.g., in the manner of insertion used for a Foley catheter)without requiring an external incision or a tissue path from theexternal incision to the urethra. The use of positioning features canavoid the need for an optical component for locating a distal end.Exemplary positioning features include one or combinations of: visibledistance demarcations at the proximal end that can be used to gauge thelocation of a distal end, an injection orifice, or positioning feature(e.g., balloon) relative to the prostatic urethra or bladder; knowndimensions of the device; one or more balloons; tissue tensioners; orother positioning features at the distal end of the shaft. Also usefulto avoid the need for an optical feature are moveable features such as amoveable injection orifice, to allow movement of an injection orificealong a length of the device after the device may be to some degreefixed internally, e.g., within the urethra.

According to devices of the invention, one or multiple injectionorifices are located at the distal end of the device at a location orlocations along the shaft that place the orifice or orifices at adesired location internal to the patient upon installation, e.g., withinthe urethra proximal to the prostate (i.e., the prostatic urethra). Theorifice or orifices are in fluid communication (e.g., through aninjection lumen) with a fluid source that can be pressurized to ejectfluid from the injection orifice and into a tissue, e.g., through theurethra and into the prostate. The injection lumen that connects theinjection orifice to the proximal end of the device (and the fluidsource) extends along a length of the shaft and is of a material thatcan withstand a pressure produced during ejection. Multiple orifices maybe arranged at different locations around the perimeter of the shaft, ormay be located at different lengths along the shaft, or both.Optionally, an orifice or orifices may be moveable relative to theshaft, either rotationally around a longitudinal axis of the shaft orlengthwise along a length of the shaft. Each of multiple orifices may beconnected separately to the pressurized fluid source to allow fluid tobe separately ejected from each orifice, if desired; or multipleorifices may be connected together to a fluid source to allow ejectionfrom multiple orifices at once.

An injection orifice may have any useful size (e.g., length anddiameter) for producing desired properties of an injection such asdesired exit velocity, injectate volume, injectate dispersion (e.g.,size and shape of a cloud of injected particles), etc. Examples ofuseful orifice diameters may be in the range from about 0.001 to 0.05inches, depending on factors such as the desired injection parametersand the type and size (e.g., depth) of tissue being injected. Theinjection orifice may be larger or smaller than the injection lumenadjacent to the injection orifice, if desired, to affect the exitvelocity of the injectate at the injection orifice. Examples of usefulorifice shapes may include features such as a venturi, a continuousuniform diameter along the length of an orifice, a funnel-shape, etc. Asis known, a relatively smaller diameter orifice may produce an injectiondepth of greater penetration into tissue compared to a larger diameterorifice (with identical injection pressure).

According to particular embodiments, an orifice may be included at alocation of a shaft as part of a larger structure that can be referredto as an “injector head.” An injector head can be considered to be acomponent of a needleless injector device that includes one or multipleinjection orifices and one or more functional surfaces, in variousarrangements. Examples of functional surfaces include a surface thatcontacts internal tissue (e.g., urethral tissue) during an injectionstep, and a surface that includes an injection orifice, the two of whichmay or may not be the same. Any one or more surface of an injector headmay be flat, arcuate, curved, etc. A surface that contacts internaltissue during injection may include one or multiple injection orifices,or other features (such as one or more vacuum orifices as described inmore detail below), and may be shaped and sized to produce a desiredeffect on the tissue such as to place tension on the tissue. Optionally,an injector head may be moveable relative to the shaft eitherrotationally around the longitudinal axis of the shaft or lengthwisealong a length of the shaft.

Also optionally, embodiments of injector heads may include a firstsurface that contacts internal tissue during injection and a secondsurface that includes one or more injection orifices, the second surfacebeing displaced from the first surface by a small distance and beinglocated on the injector head to not contact internal tissue duringinjection. According to this embodiment an injector head is designed toplace an injection orifice at a desired distance away from internaltissue during injection for the purpose of affecting and controllingfeatures of the injectate upon injection, such as the degree to whichinjectate particles become dispersed throughout injected tissue (e.g.,prostate tissue) and the distance of travel (penetration) of dispersedinjectate particles. As an example, an injector head may include arecessed flat surface that includes one or multiple injection orifices,and a second surface that surrounds the first surface, the secondsurface being proximal to the first surface but displaced a smalldistance above the first surface. The distance (if any) between aninjection orifice and tissue into which injectate is delivered canaffect the penetration distance of the injectate—a relatively smallerdistance between tissue and an orifice will result in increasedpenetration of an injection compared to a similar injection from agreater distance.

The injector head can be of a material such as a metal that is useful toprovide an injection orifice capable of delivering a high-pressureinjection as described herein. The injector head can be stationary ormay be moveable along the length of the shaft of the injector device.Alternately or in addition the injector head may be moveable in arotational direction around the longitudinal axis of the shaft of theneedleless injector device.

A pressurized fluid source is connected to an injection orifice by aninjection lumen. To accommodate an operating pressure necessary toinject fluid through tissue (e.g., to transverse the urethra and travela distance into the prostate), the injection lumen must be formed of amaterial that also withstands the injection pressure. Depending on theoverall design and features of a device, an injection lumen may beeither flexible or rigid, and may be formed of rigid metal, a flexiblemetal, a flexible polymer, a reinforced polymer composite, etc., any ofwhich will withstand a useful injection pressure.

The pressurized fluid source can include a source of fluid and a sourceof pressure (“pressure source”). The pressure source may be mechanical(such as a spring), pneumatic, hydraulic, electric, etc., as will beunderstood. The pressure source may be mechanically or electronicallycontrolled. The pressure source can cause a fluid contained in a fixed-or variable-volume chamber to be pressurized to a transient pressure, atthe injection orifice, that is sufficiently high to allow the fluid tobe ejected from the injection orifice with sufficient force to penetrateinternal tissue such as to traverse the urethra and to then penetrate adesired distance into the prostate.

Additional potential features of injector devices of the invention, foroptional use in combination with other features described herein,include inflatable balloons located at the distal end of the shaft ofthe injection catheter, e.g., as “positioning features.” An injectordevice may include one or multiple balloons at a distal end, allowingthe device to be placed and fixed at a desired position during use. Aballoon for locating the injector device can be particularly useful incombination with a device that does not include any optical feature suchas an endoscope to directly view the operation of distal features of thedevice such as an injection orifice. Placement of a balloon at thedistal end of the device, at a known distance from an injection orifice,can facilitate proper placement of the injection orifice, such as withinthe prostatic urethra, based on the positioning of the balloon.

An example of a balloon that allows a surgeon to locate an injectordevice as desired is a balloon that can be placed within the bladder orat the bladder neck when the device is installed. The balloon may be ofa type used in a Foley catheter but adapted to function at the end ofrigid or flexible shaft of a needleless injector device as describedherein. The balloon can be useful to fix the overall location of thedevice during use, i.e., to place the shaft of the device at a desiredlocation to cause one or more injection orifices to be located asdesired, e.g., within the prostatic urethra. The balloon can be locatedon the shaft at a location distal to the injector head. When the deviceis installed, the balloon can be in the bladder or bladder neck, and canproperly locate the device during treatment, and can also seal thebladder neck from the prostatic urethra.

Another optional feature of an injector device of the invention, foroptional use in combination with other features described herein, is aninflatable “proximal” balloon located at the distal end of the shaft ofthe device but on the proximal side of an injection orifice or orifices.A proximal balloon can be designed to also locate and fix the locationof the device during treatment. Additionally, a proximal balloon canfunction to seal the proximal (lower) end of the urethra. With a balloonsealing the distal end of the urethra (e.g., at the bladder or bladderneck) and a proximal balloon sealing the proximal end of the urethra,the balloons can together define a “zone of treatment” within theurethra that extends approximately the length of the prostate or thelength of a desired portion of the prostate that will be treated. Theballoons seal the ends of the prostate, which advantageously preventsinjectate from passing outside of the zone of treatment within theurethra.

Another feature of a needleless injector device for optional use incombination with other features described herein, is a tissue tensionerlocated at a distal end of the device. A tissue tensioner is located atthe shaft, somewhat near to an injection orifice, e.g., to be within theprostatic urethra and near the injection orifice when the device isinstalled. A tissue tensioner can be a mechanism capable of contactingtissue, e.g., urethral tissue, to hold a desired portion of the tissuein place relative to an injection orifice, and to optionally produce atension or strain on the tissue in a manner that can affect the mannerin which injectate penetrates the tissue and becomes distributed in thetissue upon injection. While a tissue tensioner can be used incombination with any of the other features described herein, includingrigid shaft embodiments of devices, a tissue tensioner may beparticularly useful when used with a device that includes a flexibleshaft. The tissue tensioner can facilitate a good result upon injectionof fluid through the urethra by ensuring that the internal urethraltissue is fixed and includes a desired amount of tension for receivingan injection.

Depending on the configuration of an injection orifice at a shaft of adevice, or at an injector head, a tissue tensioner can be used to placea desired portion of tissue in direct contact with an injection orifice,i.e., a surface that contains an injection orifice. Alternately, atissue tensioner can place a desired portion of tissue at a desireddistance away from an injection orifice, e.g., in the instance of aninjector head that includes two surfaces with a recessed surfaceincluding an injection orifice. The distance, if any, between aninjection orifice and tissue, at injection, can be selected to affectproperties of the injection, e.g., to affect the distance an injectatepenetrates into tissue, the size of droplets, and the pattern over whichdroplets of injectate are dispersed throughout tissue when injected.Other factors can also be adjusted to affect properties of the injectionsuch as pressure and volume of injectate, size and shape of theinjection orifice, etc.

Examples of types of tissue tensioners include inflatable balloonslocated at a shaft near an injection orifice, and mechanicallyextendable or retractable components such as paddles, protrusions,levers, metal cages, and the like, any of which can be extended from ashaft of an injector device to place pressure on internal tissue, e.g.,on urethral tissue within the prostatic urethra.

A balloon or a mechanically extendable or retractable tissue tensionercan be inflated or extended at a location that is approximately at alength along a shaft that is near an injection orifice. When used withina urethra, the tissue tensioner can push urethral tissue away from theshaft in a manner that causes urethral tissue and an injection orificeor injector head to contact each other. This can be done, for example,by a balloon expanding from an opposite side of a shaft relative to aninjection orifice, to place pressure on urethral tissue located oppositefrom an injection orifice and to cause the injection orifice or a nearbysurface to meet, optionally to produce pressure, strain, or tension onthe urethral tissue opposite of the balloon. A mechanical tensioner maybe extended from a shaft of a device by use of an actuating mechanismsuch as a mechanical connection between the tensioner and the proximalend of a device.

Another embodiment of tissue tensioner can be a pressure differentialproduced by vacuum. Vacuum can be created near an injection orifice, forexample, in a manner that can pull urethral tissue and an injectionorifice or injector head into contact, and optionally place a tension orstrain on the tissue of the urethra at the location that will receiveinjectate. This can be done, for example, by including vacuum orificesnear an injection orifice, e.g., along a shaft or at an injector head.The vacuum orifice can pull vacuum causing the shaft or injector head tocontact the internal tissue of the urethra near the injection orifice,causing the urethral tissue to contact the catheter shaft or injectorhead. The vacuum orifice can be in fluid communication with the proximalend of the device through a lumen extending along the shaft, e.g., avacuum lumen.

Embodiments of injector devices of the invention, in addition to any oneor more of the above-described features, in any combination, may includesafety features that prevent inadvertent or improper actuation of adevice or inadvertent or improper ejection of fluid from a device.Examples of a safety feature may be any feature that prevents actuationof an injection mechanism if a device is not properly installed andproperly located, internally, with the device and injectate in a readyposition to make a desired injection.

One example of a safety mechanism that would prevent actuation of aninjection mechanism if injectate fluid is not present at an injectionorifice or an injection lumen may be an air detector located at theinjection orifice or injection lumen. This mechanism would directlydetermine whether an injectate fluid is present in an injection lumenand at an injection orifice. A fluid may be detected by knowntechniques, such as by detecting microscopic bubbles in a fluid usingultrasound or optical methods. If fluid is not present the device wouldbe programmed to prevent actuation of the injection mechanism.

Another type of safety mechanism that would prevent actuation of aninjection mechanism, if injectate is not present at an injection orificeor an injection lumen, is a priming mechanism to ensure that a fluid islocated properly within an injection lumen upon manufacture, sale, orduring use of a device. This type of a safety feature does not directlydetermine whether an injectate fluid is present in an injection lumenand injection orifice, but provides a level of assurance that injectateis properly located within the device for injection by allowing for apriming step. A priming mechanism could be used in combination with anair sensor described above.

Optionally, embodiments of the invention can include a device sold in apre-primed condition (optionally in a sterilized package), with a fluidcontained within the injection lumen. The fluid may be, e.g., ananesthetic, saline, an antibiotic, ethanol, or another biologic agent,depending, for example, on the intended use of the injector device. Theinjector device can be pre-primed, meaning that the injector device isin a primed condition as supplied to a surgeon. The pre-primed injectordevice can be primed during manufacture and prior to distribution andsale, e.g., a device can be packaged and sold to a user in a primedcondition. When a surgeon or assistant removes the device from asterilized package, the device is already primed and may include adesired amount and type of injectate fluid within the injection lumenand, optionally, a reservoir or other chamber at the proximal end. Thesurgeon may use the device without having to prepare the device by,e.g., adding injectate fluid to the device or priming the device toplace injectate fluid into the injection lumen. Optionally thepre-primed device may be disposable.

In general, a priming mechanism can be any mechanism that is useful toplace fluid in an injection lumen prior to a high-pressure injectioninto tissue. During normal use, prior to making an injection, fluid maybe contained by a fluid chamber at a proximal end of the injector, whichis in fluid communication with the injection lumen and injectionorifice. To prime the device, injectate is caused to flow at relativelylow pressure from the fluid chamber into the injection lumen, to fillthe injection lumen until injectate flows (e.g., slowly) from theinjection orifice. Low pressure flow may be produced, e.g., by applyingpressure to the fluid in the fluid chamber, by use of a pressure sourceas described herein. Low pressure flow is a rate of flow that would notallow injectate flowing from the injection orifice to penetrate tissue,and typically is greatly below a rate of flow that would allow tissuepenetration.

Embodiments of injector devices of the invention, in addition to any oneor more of the above-described features, in any combination, may includestill further features that add convenience or efficiency to aneedleless injector device. Examples include specific triggermechanisms, actuating systems, or control systems (e.g., electronic andcomputerized control systems) that allow for multiple injections, andmethods and features for controlling or programming volumes, depths,timing, order, positioning, or other features of one or multipleinjections.

In particular embodiments, a trigger and control system could include aseries of multiple positions that produce multiple actuations such asengagement of a tissue tensioner, actuation of an injection mechanism,movement of an injector head, etc. For example, a first trigger positionmay cause engagement of a tissue tensioner and a second trigger positionmay cause the injector to be actuated to inject fluid. Any individualcomponent, or an entire device, could be disposable or reusable.

As an example, a disposable or reusable optical feature such as anendoscope could be incorporated into a portion or component of a devicethat is either disposable or reusable. Additionally or alternately, adevice could have a reusable pressure source (e.g., cartridge ofpressurized gas), a replaceable fluid reservoir, a disposable injectorhead portion, or may be entirely disposable.

In another particular embodiment, a device could be designed to injectmultiple volumes of injectate at different tissue locations.Accordingly, the injections may be made between steps of relocating aninjection orifice, wherein the injection orifice may optionally bemoveable relative to the shaft. The multiple volumes of injectate couldbe pre-loaded into individual, e.g., replaceable, vials of apredetermined volume as desired for a single or multiple injections,i.e., a single vial may include a single dose (volume) or multiple doses(volumes) of injectate. With the use of a replaceable vial, the devicecould be used to inject one or multiple doses of injectate using theentire volume from one vial. The replaceable vial could then be removedfrom the injector device and replaced with a full vial, and the volumeof the full vial could be injected in one or more injections. This couldbe repeated for as many injections as desired. In alternate embodiments,the device may have a connection at the proximal end for connecting thedevice to a source of injectate fluid (e.g., a “hopper”) from whichmultiple injections of desired volumes could be sourced without the needfor loading or reloading individual vials.

With any of the above features of injector devices, a device couldinclude an electronic process control system that can be programmed todeliver injections having various locations, volumes, and otherinjection properties such as depth and degree (e.g., shape and distance)of dispersion and size of particles of injectate.

The attached figures illustrate various features of injector devices asdescribed and for use in treating a prostate.

FIG. 1 illustrates injection catheter 10, which includes threestationary injector heads 2 along a portion of shaft 16. Each ofinjector heads 2 includes injection orifice 4 at the center of injectionhead 2 and vacuum orifices 6 surrounding each injection orifice. Distalend balloon 8 is located at tip 14 of device 10 and can be used to fixand locate device 10 during use by being inflated within the bladder orbladder neck. Proximal balloon 12 can be used to fix and locate device10 during use by being inflated within the urethra, e.g., at theproximal end of the prostatic urethra. Tip 14 includes drainageapertures 18 connected to a proximal end of the device (not shown) bydrainage lumen 20. Each of injection orifices 4, vacuum orifices 6, anddistal and proximal balloons 8 and 12, are in fluid communication with adistal end of the device, by lumens 22, located for illustration withinthe sidewalls of shaft 16.

FIG. 2 illustrates a portion of another embodiment of an injectordevice. Device 30 includes shaft 32; a tissue tensioner in the form ofexpandable metal cage 34; and moveable injector head 38, which can bemoved along a length of shaft 32 within slot 36. Injector head 38connects to a proximal end of device 30 through moveable injection shaft31, which extends within a hollow center of shaft 32. Injector head 38includes a ring of eight vacuum orifices 42 surrounding a centralinjection orifice 44. Actuating mechanism 40 is located within a lumenof a wall of shaft 32, and can be actuated to cause extension andretraction of expandable metal cage 34.

FIG. 2 a illustrates a cut-away side view of injector head 38, includingvacuum orifices 42 and injection orifice 44. FIG. 2 a specificallyillustrates vacuum lumens 43 and injection lumen 45, which are in fluidcommunication with a proximal end of device 30 through moveableinjection shaft 31.

FIG. 3 illustrates a portion of another embodiment of an injectordevice. Device 50 includes shaft 52; a tissue tensioner in the form ofexpandable balloon 54; and moveable injector head 58, which can be movedalong a length of shaft 52 within slot 56. Injector head 58 includes aring of vacuum orifices 66 included on a surface 62. Recessed surface 64includes injection orifices 68 (three orifices as illustrated). Lumen 60is located within a wall of shaft 52, and is in fluid communication witha proximal end (not shown) of device 50, to allow inflation of balloon54. Injector head 58 connects to a proximal end of device 50 throughmoveable injection shaft 51, which extends within a hollow center ofouter shaft 52.

FIG. 3 a illustrates a cut-away side view of injector head 58, includingvacuum orifices 66, injection orifices 68, surface 62, and recessedsurface 64. FIG. 3 a specifically illustrates vacuum lumens 67 andinjection lumens 69, which are in fluid communication with a proximalend of device 50 through moveable injection shaft 51.

FIGS. 4 a, 4 b, 4 c, and 4 d, each illustrate various alternateembodiments of tissue tensioners, as could be incorporated into any oneof the injector devices illustrated or described herein. FIG. 4 a showsdevice shaft 70 inside of urethral tissue 72. Injection orifices 74 areincluded at surface 76, which is recessed from outer surface 79 of shaft70, proximal to injection orifices 74. Tensioner 78 is extendable andretractable by use of an actuating mechanism (not shown) within theinjector device. Tensioner 78 is shown in an extended state wherebytensioner 78 contacts tissue 72 on a side of the urethra that isopposite of the tissue that will be contacted by fluid ejected frominjection orifices 74. Orifices 74 and surface 76 are not in directcontact with urethral tissue but are separated by a small distancedefined by the distance that surface 76 is recessed from surface 79. Bycontacting and pushing tissue opposite of orifices 74, urethral tissue72 and surface 79 are placed into contact. Tissue 72 near surface 79 isstretched or tensioned to a desired extent, to affect or control themanner in which an injectate dispersed at high pressure from orifices 74will penetrate urethral tissue 72 and become dispensed in prostatetissue (not shown).

FIG. 4 b illustrates another embodiment of a tissue tensioner in theform of an inflatable balloon located near an injection orifice. FIG. 4b shows shaft 80 inside of urethral tissue 82. Injection orifices 84 areincluded at surface 86, which is recessed from the outer surface 89 ofshaft 80, proximal to orifices 84. Tensioner 88 is a balloon that can beinflated and deflated through an inflation lumen (not shown) within theinjector device and in fluid communication with a proximal end of thedevice (also not shown). Tensioner 88 is shown in an inflated statewhereby tensioner 88 contacts tissue 82 on a side of the urethra that isopposite of the tissue that will be contacted by fluid ejected frominjection orifices 84. Orifices 84 and surface 86 are not in directcontact with urethral tissue 82 but are separated by a distance definedby the distance that surface 86 is recessed from surface 89. Bycontacting and pushing tissue opposite of orifices 84, urethral tissue82 and surface 89 are placed into contact. Tissue 82 that is nearsurface 89 is stretched or tensioned to a desired extent to affect orcontrol the manner in which an injectate (dispersed from orifices 84)will penetrate urethral tissue 82 and become dispensed in prostatetissue (not shown).

FIG. 4 c illustrates another embodiment of a tissue tensioner in theform of vacuum orifices located near an injection orifice of aninjection catheter. FIG. 4 c shows injection catheter shaft 90 inside ofurethral tissue 92. Injection orifices 94 (three illustrated) areincluded at surface 96, which is part of an injector head 97 thatextends from the outer surface 99 of shaft 90, proximal to orifices 94.Tensioner 98 is in the form of multiple (four as illustrated) vacuumorifices located at surface 96 of injector head 97, near orifices 94.Vacuum orifices 98 can create a vacuum force at injector head 97, nearorifices 94, through a vacuum lumen (not shown) within the device and influid communication with a proximal end of the device. Vacuum orifices98 can create a pressure differential that causes tissue of urethra 92to contact injector head 97, as shown, in a manner that will placeurethral tissue 92 in direct contact with injector head 97 and injectionorifices 94.

FIG. 4 d illustrates another embodiment of a tissue tensioner in theform of vacuum orifices located near an injection orifice. FIG. 4 dshows shaft 100 inside of urethral tissue 102. Injection orifices 104are included at recessed surface 106, which is recessed from the outersurface 109 of shaft 100, proximal to orifices 104. Tensioner 108 is inthe form of multiple (four as illustrated) vacuum orifices 108 locatedwithin shaft 100, near orifices 104. Vacuum orifices 108 can create avacuum force at surface 109 of shaft 100, near orifices 104, through oneor more vacuum lumens (not shown) within shaft 100 and in fluidcommunication with a proximal end (not shown) of the device. Injectionorifices 104 and surface 106 are not in direct contact with urethraltissue 102, but are separated by a distance defined by the distance thatsurface 106 is recessed from surface 109. Vacuum orifices 108 can createa pressure differential that causes tissue of urethra 102 to contactsurface 109 of urethral shaft 100.

FIGS. 5, 5 a, and 5 b illustrate features of an embodiment of a deviceof the invention that includes a multi-component, rigid shaft. FIG. 5shows the device in an assembled condition and FIG. 5 a shows the devicein an unassembled condition. Device 200 includes a rigid shaft 202, mainbody 204, optional scope 206 (illustrated to be removable), and powersource 212. Power source 212, illustrated to be removable, includesfeatures for providing injectate fluid and pressure to inject the fluid,e.g., a permanent or removable supply of injectate fluid in fixed-volumereservoir 218; a pressurizing mechanism (e.g., a plunger, bellows,syringe, etc.) 214 within a variable-volume chamber 215, and; a pressuresource 216 for supplying pressure to pressurizing mechanism 214, whichmay be pneumatic, hydraulic, mechanical (e.g., a spring), electric,pressurized gas such as a carbon dioxide cartridge, an external sourceof pressurized gas or fluid, etc. Also included in power supply 212 butnot specifically shown in FIGS. 5, 5 a, and 5 b, are mechanisms such asvalving and tubing, etc., to allow reservoir 218, pressurizing mechanism214, and pressure source 216, to work together to pressurize a fluid forinjection through injection lumen 220.

Scope 206 includes scope shaft 208 and eye-piece 210. Scope 206 may be acommercially available rigid endoscope such as a cystoscope orlaparoscope, for example. Suitable cystoscopes are available, forexample, from ACMI (Classic and Elite models), Storz, Wolf and Olympus.

Main body 204 includes a port designed to mate with a power source 212,which can deliver a pressurized fluid injectate to main body 204. Shaft202 includes injector lumen 220 and optical lumen 222. Injector lumen220 aligns with a lumen of power source 212 such that pressurizedinjectate flows from power source 212 through injector lumen 220 and toan injection orifice at a distal end (not shown) of shaft 202.

Rigid shaft 202 includes optical lumen 222 to contain shaft 208 of scope206, when the device is in an assembled condition. Rigid shaft 202 canbe of a rigid material such as a metal and includes orifices or aninjector head (not shown) at the distal end for injecting an injectatefluid. When optical scope 206 is placed within optical lumen 222 ofshaft 202, scope 206 allows viewing of internal tissue for performing aninjection.

Referring to FIG. 5 b, a distal end 230 of device 200 is illustrated.Shaft 202 includes injection head 224, at the far distal end. Injectionhead 224 includes injection orifice 226 in fluid communication with aproximal end of device 200 through injection lumen 220. Distal end 228of endoscope 206 is illustrated as inserted inside of optical lumen 222,and is illustrated to be removable. During use, the surgeon can view thearea above injection head 224 and injection orifice 226 by viewingthrough eyepiece 210 of endoscope 206.

Device 200 can include one or more other functional features describedherein but not specifically illustrated in FIG. 5, 5 a, or 5 b. Forexample, rigid shaft 202 can include a tissue tensioner, one or multipleballoons, or a tensioner and one or more balloons, each connectedthrough lumens to a proximal end of the device. Alternately, injectionhead 224 may include a tissue tensioner, e.g., in the form of vacuumorifices.

An embodiment of exemplary details of a body of a needleless injectordevice is shown in FIG. 6. FIG. 6 shows body 240 of a needlelessinjector device. An outer shaft 242 (rigid or flexible) extends from anend of body 240 to a distal end (not shown). Injection lumen 246 isdefined by or contained by shaft 242 and is in fluid communication withvariable-volume chamber 248. A pressurizing mechanism 250 (e.g.,plunger) partially defines the volume of chamber 248 that is forcontaining injectable fluid and pressurizing the fluid. Pressure source252 works with pressurizing mechanism 250 to move mechanism 250 toadjust the size of chamber 248 or to pressurize a fluid contained inchamber 248. Reservoir 254 can contain fluid injectate that can becaused to flow through valve 256 into chamber 248. Reservoir 254 may bepermanent or may be removable from body 240.

Body 240 includes features of the invention useful to prime injectionlumen 246 prior to use of the needleless injector device for delivery ofinjectate. For a priming operation, as will be appreciated, chamber 248and injection lumen 246 may start partially or completely empty ofinjection fluid, and may contain a gas (e.g., air). According to theillustrated embodiment of body 240, to begin priming lumen 246 an amountof injection fluid is passed from reservoir 254 through valve 256, e.g.,an amount to allow for lumen 246 to be filled (primed) and to still havesufficient injectate fluid remaining in chamber 248 for one or moredosage volumes to be injected from the needleless injector device. Forexample, fluid can be drawn from a filled reservoir 254 by openingvalves 256 and 257, and drawing back piston 250 to increase volumewithin chamber 248. After placing fluid in chamber 248, to prime lumen246, valve 256 is closed and pressure source 252 is actuated to causeplunger 250 to move forward and reduce the volume of fluid withinchamber 248, i.e., forcing fluid into lumen 246. When lumen 246 is full,e.g., as shown by injectate fluid flowing from an injection orifice (notshown) at the distal end of shaft 242, priming is complete. Afterpriming, an injection of injectate fluid can be delivered by againactuating supply 252 to cause plunger 250 to move further, this time topressurize the remaining volume of fluid within chamber 248 and delivera desired dosage of the fluid through injection lumen 246 for highpressure injection into tissue. The desired dosage may be all or only aportion of the fluid remaining in chamber 248 following priming.

The invention also provides a method of delivering fluid to tissue ofthe lower urinary tract, e.g., prostate tissue, including the steps of:providing a pressurized fluid source and a needleless injector devicesubstantially as described above; inserting the needleless injectordevice into the patient; navigating the device until an injectionorifice at a distal end of the device is positioned at a desiredinjection site; and actuating the device to inject fluid into tissuesuch as the urethra or prostate. By using a high-pressure needlelessinjection system, as opposed to a needle, the invention reduces traumaas compared to needle-based systems. Further, the injectate canadvantageously be dispersed throughout a tissue instead of pooling. Inaddition, the high-pressure needleless injection system can reduce otherundesired effects that occur by injection using a needle such as theneed for overdosing, and the amount of injectate required is reduced.

Exemplary methods that can be performed using devices described hereininclude methods that relate to treating diseased prostate tissue. Oneform of treatment regimen includes the steps of chemically ablatingprostate tissue sufficiently to elicit a reparative process in theabsence of further treatment. The size of the prostate is reducedrelative to the size prior to treatment. The treatment regimen issuitable for treatment of prostate tissue diseases including BPH andprostatic carcinoma.

FIG. 7 shows the anatomical position of prostate 300 (including laterallobes 302) surrounding urethra 304, and adjacent tissue includingseminal vesicles 306, bladder neck 308, and pelvic tissues includingsphincter muscles 310. Chemical ablation may be achieved, for example,by direct transurethral injection of a chemoablation fluid into apatient's prostate. The terms “ablate,” “ablation,” and “ablating,” oftissue means causing a reduction in tissue mass. One suitable manner ofablating tissue is by causing a decrease in the number of tissue cells.The phrase “chemical ablation” includes processes whereby tissue mass isreduced by action of a chemical or biological agent on the tissue, suchas ethanol. One suitable procedure for chemically ablating prostatetissue in accordance with the treatment regimen is by injection ofethanol (absolute alcohol) into the prostate to be treated. The ablatingaction of ethanol is due to several processes, including dehydration ofcells, coagulation of proteins, and thrombosis of vessels that feed thetissue.

According to needleless procedures of the invention, an injectate suchas ethanol can be injected into prostate tissue transurethrally in amanner that disperses particles or droplets of the injectate throughoutprostate tissue. The manner in which the injectate enters and becomesdispersed throughout the prostate can be characterized by variouscontrollable factors such as one or more of the following: the deliverypressure at the injection orifice, the size and shape of the injectororifice, the volume of injectate delivered, the distance of theinjection orifice from the internal urethral tissue at injection, andthe amount of pressure or tension placed on the internal urethral tissueat the time of injection (e.g., by a tissue tensioner). Generally,higher injection pressure results in deeper penetration of theinjectate; a smaller orifice (based on constant injection pressure)results in deeper penetration of the injectate; and a reduced distancebetween orifice and tissue results in deeper penetration of theinjectate.

Methods of treatment can include one or multiple discrete steps relatingto insertion of an injector device as described herein; positioning ofthe device to place one or more injection orifices at desired locationswithin the prostatic urethra; optionally, actuation of a tissuetensioner; optionally, use of an optic device; transurethral injectionof an injectate using a needleless mechanism; optionally, one ormultiple steps of re-positioning of one or more injection orifices;optionally, one or more additional steps of transurethral injection.

Some steps may differ or be included or excluded from specific methodsof treatment, or may be used with small or significant variations,depending on the type of injector device and specific features of thedevice. For example, an insertion step may differ for a rigid-shaftdevice and a flexible-shaft device—a flexible shaft (e.g., an injectioncatheter) may be inserted through the external opening of the urethra(the meatus) whereas a rigid shaft device may require an externalincision and a tissue path that leads to the urethra. A device thatincludes a multi-component shaft may be inserted by multiple steps,i.e., one for each component of the multi-component shaft, whereas adevice that includes an integral shaft is inserted as a single unit. Amethod of using a device that includes multiple stationary injectionorifices may involve an injection from each of the orifices, whereas amethod of using a device that includes a moveable injection orifice mayinclude steps of making an injection, moving the injection orifice, andmaking another injection.

During an injection step, a needleless injector device causes a volumeof injectate to be ejected from an injection orifice as a fine,high-pressure stream. The stream passes through tissue, e.g., throughthe urethra and into the prostate. The stream can become dispersed intotiny droplets that travel separately and disperse throughout theinjected tissue. Ultimately, the injectate becomes distributed as a finemist of tiny particles that enter and travel over a range of depths anddirections into the injected tissue (e.g., prostate), to produce a“cloud”-type penetration of the injectate throughout the tissue. Eachparticle of injectate can preferably remain within the injected tissue,although when injecting the prostate, a portion of a total amount ofparticles may become located within gland ducts where that portion ofinjectate could flow to the urethra. As opposed to the use of a needle,the injectate of the needleless procedure does not pool at one locationand does not require a slow injection rate. Also, even though a portionof the injected particles may arrive at a location that includes a glandduct, the possibility that those particles will flow from an injectedprostate and to the urethra is relatively small because the particlesare sufficiently dispersed that they may not collect to sufficientvolume to produce a flow.

The injectate may be characterized in terms of any one or more of thefollowing: volume of individual injections; volume total injectate: sizeof dispersed particles (e.g., average size); and the dispersal pattern,including directional dispersion, depth of individual particles, andaverage depth. These factors can be affected or controlled as desired,by selecting features or operating parameters of the injection stepitself. Specifically, above-referenced features can be affected andcontrolled by adjusting one or more of: the injection pressure;injection volume; number of injections; distance from the injectionorifice to tissue at injection; and the type of injection orifice.

Briefly, a TEAP procedure may be performed using a needleless injectordevice such as illustrated or described herein, or using devices thatare similar or analogous to those illustrated or described.

FIG. 8 illustrates a method involving a flexible-shaft injectioncatheter to inject fluid into a prostate. Injection catheter 320includes a distal end that includes a portion of shaft 322 positionedwithin prostatic urethra 304, and a proximal end (not shown) thatremains external to the patient. Injection catheter 320 also includespositioning features in the form of proximal and distal balloons 324 and326, respectively, at locations along shaft 322. Moveable injector head328 is located at the end of moveable injection shaft 330. Moveableinjection shaft 330 is flexible and moveable along a length of shaft322, to allow movement of injector head 328 within slot 332 of shaft322. Injector head 328 is illustrated to include injection orifice 334and vacuum orifices 336, each of which is in fluid communication with aproximal end of device 320 through lumens (not shown) within a length ofmoveable injection shaft 330. Proximal and distal balloons 324 and 326are in fluid communication with the proximal end of device 320 throughlumens 338 defined by the sidewall of shaft 322. Drainage apertures 340are located at the end of shaft 322 to be inside of bladder 344 whendevice 320 is installed, and are in communication with the proximal endof device 320 through drainage lumen 342.

In use, shaft 322 is advanced into position within urethra 304 such thatinjector head 328 is within prostatic urethra 304. This can be done byinserting flexible shaft 322 through the external orifice of the urethra(meatus) or by preparing an external incision and a tissue path leadingto the prostatic urethra. To identify and fix the proper internallocation of shaft 322 and injection orifice 328 within urethra 304,distal balloon 326 becomes located within bladder neck 308 and proximalballoon 324 becomes located at the proximal end of prostatic urethra304, optionally sealing the ends of prostatic urethra 304. The spacewithin prostatic urethra 304 between proximal balloon 324 and distalballoon 326 can be referred to as the zone of treatment.

According to this embodiment of a needleless injector device and methodof treatment, injection catheter 320 does not include an optical featureto view injection orifice 334 during positioning or use, or to otherwiseallow placing injection orifice 334 or injector head 328 at a desiredlocation within prostatic urethra 304 during installation and treatment.Instead, injection catheter 320 can be used by a “blind delivery” methodthat places injector head 328 and injection orifice 334 at desiredlocations within prostatic urethra 304 by use of distal and proximalballoons 326 and 324, in combination with knowledge of the dimensions ofthe features device 320 such as the distances between balloons 324 and326 and the distances from balloons 324 and 326 to distal and proximalends of slot 332.

FIG. 8 illustrates device 320 that includes a moveable injector head 328that can allow for injection of injectate fluid at different positionsof prostatic urethra 304, when installed. Alternately, according toother variations of device 320, shaft 322 may include multiple injectionorifices along the length of shaft 322 within the zone of treatment, oraround the perimeter of shaft 322 within the zone of treatment.

Once shaft 322 is positioned within prostatic urethra 304 asillustrated, injection catheter 320 is used to deliver one or multipletransurethral injections of injectate using a needleless mechanism thatincludes injection orifice 334. The procedure may include one ormultiple steps of re-positioning injector head 328 by moving injectorhead 328 within slot 332 to treat all portions of a prostate.

FIG. 9 illustrates a method using a rigid, e.g., multi-piece shaft,needleless injector device to inject fluid transurethrally into aprostate. As illustrated, device 420 includes a distal end that includesa portion of shaft 422 positioned within prostatic urethra 304. Aproximal end (not shown) of the device remains external to the patient.Device 420 as illustrated does not include a positioning feature such asa balloon along shaft 422, although a balloon or other positioningfeature may optionally be included at any desired location along shaft422. Device 420 may include an endoscope (not shown) that allows viewingof injector head 428 during use. Injector head 428 is located at the endof injection shaft 430. Injector head 428 includes injection orifice 434located at the center of injection head 428 and four vacuum orifices 436located to surround injection orifice 434. Each of injection orifice 434and vacuum orifices 436 is in fluid communication with a proximal end ofdevice 420 through lumens (not shown) within a length of injection shaft430.

In use, shaft 422 is advanced into position within urethra 304 such thatinjector head 428 is within prostatic urethra 304. This can be done byinserting shaft 422 through an external incision and tissue path leadingto urethra 304. An endoscope optionally included as part of device 420can be used to view the location of injection head 428 relative toprostatic urethra 304, to identify and properly locate injection orifice428.

FIG. 9 illustrates device 420 that includes injector head 428 that canallow for injection of fluid at different positions of prostatic urethra304, when installed, by moving shaft 422 to different locations alongthe length of prostatic urethra 304. At each desired location, injectionhead 428 is positioned as desired and suction is pulled though vacuumorifices 436 to cause the internal surface of prostatic urethra 304 tocontact the surface of injection head 428. Device 420 is then actuatedto deliver a transurethral injection from injection orifice 434, throughprostatic urethra 304, and into prostate 300. The procedure may includeone or multiple steps of positioning or re-positioning injector head 428by moving injector head 428 within prostatic urethra 304. Alternately,according to other variations of device 420, shaft 422 may includemultiple injection orifices along the length of shaft 422 or around theperimeter of shaft 422.

A chemical ablation technique according to this description can allowfor delivery of reduced dosages of therapeutic agent, e.g., a drug,other pharmaceutical agent, or ethanol or other ablative fluid, relativeto other methods that involve injection of therapeutic agent using aneedle. In general, a total amount of therapeutic agent, e.g., ethanol,injected into a prostate will depend on a variety of factors including,e.g., the size of the prostate to be treated, the shape of the prostate(i.e., length and width), the number of injection sites required,whether the median lobe is enlarged, and the nature and degree ofprostate disease. A number of methodologies can be used to estimateprostate volume, including magnetic resonance imaging (MRI), transrectalultrasonography (TRUS), digital rectal examination (DRE), and serumprostate specific antigen (PSA) level. Ethanol or another therapeuticagent may be delivered by multiple injections at multiple injectionsites, with the size of each injection and the number of injection sitesvarying according to surgeon preferences.

Where ethanol is used to chemically ablate prostate tissue,medical-grade ethanol (also known as anhydrous alcohol, absolutealcohol, or absolute ethyl alcohol) should be used in the treatmentregimens, devices, and products according to the invention. For example,190-200 proof ethanol that meets guidelines established by the UnitedStates Pharmacopeia/National Formulary (USP/NF) is a suitablechemoablation fluid in the treatment regimens of the invention.

Optionally, a chemoablation fluid may be combined with an additive thatenhances delivery or distribution of the chemoablation fluid withinprostate tissue, or that enhances the efficacy of the chemoablationfluid. The additive may be incorporated to disperse the chemoablationfluid in the vasculature of the prostate tissue more effectively, or itmay be incorporated to retain the chemoablation fluid within theprostate tissue and avoid extravasation beyond prostate tissue (i.e.,beyond the prostatic capsule).

Suitable alternative chemical ablation agents include toxins whoseeffect can be substantially contained to the tissue to be ablated. Byway of example, other alcohols, certain enzymatic solutions, and someantibiotics may be suitable agents for chemically ablating prostatetissue. In addition, other dehydrating solutions such as concentratedsaline solution may also be suitable chemoablation agents. As an exampleof a suitable alcohol, phenol (carbolic acid) has been injectedprostatically to ablate prostate tissue as a treatment for BPH. Asterile aqueous mixture of phenol, glacial acetic acid, and glycerinehas been used.

While the above description specifically describes apparatus and methodsof treating the prostate, the invention can also relate to treatment ofother tissue of the lower urinary tract, either in females or males. Forexample, the apparatus of the invention may be useful to inject theurethral tissue itself or the external sphincter, as opposed to passingthrough the urethral tissue. Further, an injectate other than anablative material may be injected into tissue of the lower urinary tract(e.g., bladder, urethra, kidneys, ureters, prostate, etc.) such asindividual or combination treatments using drugs or other therapeuticagents, e.g., botulism toxin (“botox”), an antiandrogen, among others aswill be understood. Advantages of a needleless injection of an activepharmaceutical agent is local placement of the agent to avoid systemicside effects. Specific examples of active pharmaceutical agents that maybe injected include Botulism Toxin types A through G; 5-alpha reductaseinhibitors such as dutasteride and finasteride; alpha blockers such asalfuzosin, doxazosin, prazosin, tamsulosin hydrochloride, terazosin, totreat BPH; or any of various antibiotics (e.g., to treat prostatitis)and analgesics.

Other embodiments of this invention will be apparent to those skilled inthe art upon consideration of this specification or from practice of theinvention disclosed herein. Various omissions, modifications, andchanges to the principles and embodiments described herein may be madeby one skilled in the art without departing from the true scope andspirit of the invention which is indicated by the following claims.

1. A method of treating a prostate condition, the method comprising thesteps of: preparing a needleless injector for insertion into a patient,the injector comprising: a body at a proximal end; an injection shaftextending from the body to a distal end of the injection shaft; aninjection orifice at the distal end of the injection shaft in fluidcommunication with a fluid chamber at the proximal end, the injectionorifice being positioned for fluid ejection in a lateral directionrelative to a longitudinal axis of the injection shaft; a pressuresource in communication with the fluid chamber; and an extendable tissuetensioner located at the distal end of the injection shaft proximal tothe injection orifice; inserting the injection shaft into a urethra sothe injection orifice is located within the prostatic urethra, actuatingthe tissue tensioner to contact urethral tissue, and injecting fluidfrom the injection orifice into the prostate.
 2. The method of claim 1,wherein the injector further comprises an injector head at the distalend of the injection shaft, the injector head comprising a flat surfacethat comprises the injection orifice and a vacuum orifice.
 3. The methodof claim 1, wherein the tissue tensioner comprises a retractable tissuetensioner that retractably extends from the injection shaft away fromthe injection orifice.
 4. The method of claim 1, wherein the injectorfurther comprises a first shaft extending distally from the body, andwherein the injection shaft is axially moveable along a longitudinalaxis of the first shaft.
 5. The method of claim 4, wherein the firstshaft comprises a longitudinal slot, and wherein the injection shaft islocated within the first shaft so that the injection orifice is moveablerelative to the longitudinal slot.
 6. The method of claim 1, wherein theinjection orifice is located on the injection shaft at a proximallocation relative to the distal end of the injection shaft.
 7. Themethod of claim 1, wherein the tissue tensioner is located at alength-wise position along the longitudinal axis of the injection shafton the distal end that is the same as a length-wise position of theinjection orifice such that when the distal end comprising the tissuetensioner and injection orifice is placed within a urethral lumen andthe tissue tensioner is extended, tissue of the urethra is tensioned andthe fluid is ejectable from the injection orifice to penetrate tissueunder tension.
 8. The method of claim 1, wherein the injector comprisesan injector head at the distal end of the injection shaft, the injectorhead comprising multiple injection orifices.
 9. The method of claim 1,wherein the injector further comprises an injector head at the distalend of the injection shaft, the injector head comprising a flat surface,the flat surface comprising at least one injection orifice and at leastone vacuum orifice, wherein the at least one injection orifice and theat least one vacuum orifice are in fluid communication with the fluidchamber at the proximal end through a plurality of lumens extendingalong a length of the injection shaft.
 10. The method of claim 1,wherein the step of inserting the injection shaft into the urethracomprises inserting the injection shaft through the meatus and into theurethra.
 11. The method of claim 1, wherein the step of inserting theinjection shaft into the urethra comprises preparing an externalincision and a tissue path leading to the urethra.
 12. The method ofclaim 1, wherein the injector further comprises an optical device forviewing at a distal end of the device.
 13. The method of claim 12,wherein the optical device comprises an eyepiece at the proximal end andflexible optical fiber extending from the eyepiece to a location at thedistal end of the injection shaft.
 14. A method of treating a prostatecondition, the method comprising providing a needleless injectorcomprising: a body comprising a fluid chamber, a shaft extending fromthe body to a distal end of the shaft, an injection orifice at thedistal end of the shaft, an injection lumen connecting the injectionorifice and the fluid chamber, and a priming mechanism capable offilling the injection lumen by low pressure flow of fluid from the fluidchamber; priming the injector to fill the injection lumen with injectatefluid, inserting the shaft into a urethra so the orifice is locatedwithin the prostatic urethra, and injecting fluid from the injectionorifice into the prostate.
 15. The method of claim 14, wherein the bodyof the injector further comprises a fluid reservoir, a syringe chamber,a pressure source, and a plunger adapted to the syringe chamber, theplunger cooperative with the pressure source for pressurizing thesyringe chamber, wherein the priming mechanism produces low pressureflow by the pressure source moving the plunger to cause fluid to flowfrom the syringe chamber to the injection lumen.
 16. A method oftreating a prostate condition, the method comprising the steps of:providing a needleless injector comprising: a body at a proximal end, afirst shaft extending distally from the body, an injection shaftextending from the body to a distal end of the injection shaft and ashaft terminus, wherein the injection shaft is axially moveable along alongitudinal axis of the first shaft, an injection orifice at the distalend of the injection shaft in fluid communication with a fluid chamberat the proximal end, the injection orifice being located on theinjection shaft at a proximal location relative to the shaft terminus,and the injection orifice being positioned for fluid ejection in alateral direction relative to a longitudinal axis of the injectionshaft, a pressure source in communication with the fluid chamber, and anextendable tissue tensioner located at the distal end of the injectionshaft proximal to the injection orifice, wherein the tissue tensioner islocated at a length-wise position along the longitudinal axis of theinjection shaft on the distal end that is the same as a length-wiseposition of the injection orifice such that when the distal endcomprising the tissue tensioner and injection orifice is placed within aurethral lumen and the tissue tensioner is extended, tissue of theurethra is tensioned and the injector is capable of ejecting fluid fromthe injection orifice to penetrate tissue under tension; inserting theinjection shaft into a urethra so the injection orifice is locatedwithin the prostatic urethra, actuating the tissue tensioner to contacturethral tissue, and injecting fluid from the injection orifice into theprostate.
 17. The method of claim 16, wherein the injection orifice hasa diameter in the range of 0.001 to 0.05 inches.
 18. The method of claim16, wherein the tissue tensioner comprises a vacuum.
 19. The method ofclaim 16, wherein the tissue tensioner comprises a balloon.
 20. Themethod of claim 16, comprising an injector head at the distal end of theinjection shaft, the injector head comprising a flat surface, the flatsurface comprising the injection orifice and a vacuum orifice.